Information-reading method

Abstract

An information-reading method employs an optical card including, a data section made by a linear information track, an address section for storing an address of the information track, and a guide section located adjacent to the address section and scanned before reading the address section. The address section and guide section are located at each end of said data section. The address and guide sections located at one end of the data section and the address and guide sections located at the other end of the data section are arranged in the same order in one scanning direction of the information track. The method comprises the steps of reading two addresses out of the address sections, by scanning the information track in the one scanning direction, and comparing the two addresses with each other, to thereby detect a tracking error.

What is claimed is: 
     
       1. An information reading and writing method for reading data from and for writing data onto a card-like recording medium which is scanned in a first scanning direction and a second scanning direction opposite to the first scanning direction, the method comprising: providing at least one linear information track on said card-like recording medium;   delineating a data section for storing modulated data in said at least one linear information track, said data section having first and second end portions;   delineating first and second address sections each storing modulated address data, respectively on each of said first and second end portions of said data section;   providing first and second guide sections respectively adjacent to said first and said second address sections;   the first guide section being positioned to be scanned before the first address section, and the second guide section being positioned to be scanned before the second address section when said at least one linear information track is scanned in said first scanning direction;   reading said address data out of each of said first and second address sections by scanning at least one linear information track in said first scanning direction;   demodulating said modulated data in said data section and said first and second address sections in said at least one linear information track as said linear information track is scanned in said first and second scanning directions;   serially storing the address data in said first address section in a first serial order;   serially storing the address data in said second address section in a second serial order which is the same as said first serial order; and   serially demodulating the address data in said first and second address sections,   comparing the thus read out address data from each of said address sections of said at least one linear information track with each other, to detect errors therebetween.   
     
     
       2. The method according to claim 1, further comprising: storing in each of said first and second guide sections bit synchronization pull-in data; and synchronous signal data for indicating that address data is to be scanned in said at least first scanning direction.   
     
     
       3. The method according to claim 1, wherein said card-like reading medium has a plurality of tracks, and further comprising storing track address data in each of said first and second address sections. 
     
     
       4. The method according to claim 1, further comprising providing more than one address in the address data respectively stored in said first and second address sections. 
     
     
       5. The method according to claim 1, wherein: the serial address data stored in the first and second address sections is modulated and demodulated in a given manner when the recording medium is scanned in the first scanning direction, and the serial address data stored in the first and second address sections is modulated and demodulated in a manner opposite to said given manner when the recording medium is scanned in the second scanning direction, further comprising a step of changing the demodulating manner of one of said read out address data to cause the demodulation manners to be the same.   
     
     
       6. A scannable card-like data recording medium which is scanned in a first direction and a second direction opposite to the first direction, comprising: a substantially flat card-like substrate;   a linear information track defined in said substantially flat card-like substrate;   said linear information track including:   a data section for storing modulated data, said data section having first and second end portions;   first and second address sections for storing modulated address data, which is used for tracking error detection, positioned respectively on said first and second end portions of said data section;   first and second guide sections positioned respectively adjacent to said first and second address sections;   said first guide section being positioned to be scanned before said first address section and said second guide section being positioned to be scanned before said second address section when said card-like data recording medium is scanned in said first scanning direction; and   the address data in said first address section being stored in a first serial order, and the address data in said second address section being stored in a second serial order which is the same as said first serial order.   
     
     
       7. A card-like data recording medium according to claim 6, wherein each of said first and second guide sections include: an area for storing bit synchronization pull-in data; and   an area for storing synchronous signal data for indicating address data is to be scanned in said at least first scanning direction.   
     
     
       8. A card-like data recording medium according to claim 6, further comprising: a plurality of linear information tracks defined on said substantially flat card-like substrate, each of said plurality of linear information tracks including first and second address sections which respectively store track data.